(Starch synthesis in the maize endosperm as affected by starch synthesizing mutants)
The goal of this project is to investigate the steps necessary to effect starch synthesis in developing endosperms of maize with the primary experimental probes being the mutants in which this process is disrupted. The authors have given considerable attention to the presence of a soluble enzyme complex which can synthesize de novo phospho-oligosaccharides with Glc-1-P and Glc-1,6-bisP as substrates. If Glc-1,6-bisP is not present in the reaction mixture, it can be synthesized slowly from Glc-1-P, but its presence in the reaction mixture markedly accelerates the synthesis of phospho-oligosaccharides. The enzyme complex is capable of synthesizing Glc-1,6-bisP and Glc when given either Glc-1-P or Glc-6-P as a substrate. Glc-1,6-bisP can also be formed from Fru-1,6-bisP. The enzyme complex with amylopectin and Glc-1,6-bisP as substrates will add Glc-6-P to the nonreducing ends of the amylopectin molecules. There is also a starch granule-bound phospho-oligosaccharide synthase present in the developing endosperms, but it has been less intensively investigated than the soluble form. They hypothesize that these enzymes synthesize the primers to which the enzymes capable of synthesizing alpha-1,4 glucans add glucose molecules and that their ability to utilize Glc-1,6-bisP accounts for the phosphate groups esterified to some glucose moieties of the starch.
- Research Organization:
- Wisconsin Univ., Madison, WI (USA). Lab. of Genetics
- Sponsoring Organization:
- USDOE; USDOE, Washington, DC (USA)
- DOE Contract Number:
- AC02-82ER12031
- OSTI ID:
- 5859729
- Report Number(s):
- DOE/ER/12031-T4; ON: DE91010195
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
MAIZE
BIOCHEMISTRY
OLIGOSACCHARIDES
BIOSYNTHESIS
ESTERIFICATION
GLUCOSE
LIGASES
MUTANTS
PHOSPHATES
PROGRESS REPORT
SUBSTRATES
ALDEHYDES
CARBOHYDRATES
CEREALS
CHEMICAL REACTIONS
CHEMISTRY
DOCUMENT TYPES
ENZYMES
GRASS
HEXOSES
LILIOPSIDA
MAGNOLIOPHYTA
MONOSACCHARIDES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PLANTS
SACCHARIDES
SYNTHESIS
550200* - Biochemistry